This article describes a robust, stable and fast method to describe time intensity curves for pharmacological contrast agents uptake and washout (kinetic). The model bases on the physical behavior of bolus fluids. It is data driven and does no require any further knowledge about tissue compartments. It describes kinetic flow without an arterial input function (unlike pharmacokinetic compartment models). The model has been proven in two different types of clinical settings. Perfusion-Sonography relies on the flow of blood in brain tissue. The data is heavily affected by noise, movement and low SNR. In MR-Mammography the challenges are to describe the whole contrast agents uptake and washout with few data points and to have a cheap computable model because of the largeness of the 3D-Volumes. The bolus flow was measured in MRI with a high and a low time resolution.